The present invention relates to packaging structures, and more particularly to packaging structures in which an article is held in place within an outer container by at least one plastic film. More particularly, the present invention is directed to improved methods for forming such packaging structures, and to the structures produced by these methods.
Protective packaging structures are often used when an article to be transported requires protection from physical shock, dust, dirt and other contaminants. For example, when shipping articles which may be relatively fragile, it is often desirable to package the article inside a box to protect the article from physical impacts to the box which may occur during loading, transit and unloading. In addition, when shipping sensitive electronic articles, such as computer components, it is often desirable to protect those components from dust and dirt. Aside from the shipping box itself, some additional structures are ordinarily needed to prevent the article from being damaged by uncontrolled movement within the box. Such additional structures have included paper or plastic dunnage, molded plastic foams and foam-filled cushions, among others.
One useful form of packaging for especially fragile articles is frequently referred to as a suspension package, examples of which are disclosed in U.S. Pat. No. 4,852,743 to Lewis H. Ridgeway and U.S. Pat. No. 5,388,701 to Devin C. Ridgeway. In suspension packaging, the article is suspended between two confronting sheets of plastic film. The film sheets are usually attached to corrugated frames which are sized to fit securely within a selected size box. The frame includes side and end legs which may be folded away from the film so as to space the film from the top or bottom of the box. The fact that the article is not in contact with any substantially rigid surfaces protects it from physical shock.
Suspension packaging as described above provides many advantages. In addition to the high degree of protection it provides the packaged articles, suspension packaging is conducive to an assembly line packaging procedure whereby an outer box can be formed, a first film/frame can be inserted into the box, the product to be packaged can be placed on the film within the box and can be accessed for any subsequent procedures, a second film/frame can be assembled over the product, and the box can be sealed closed. Despite these advantages, the need for two film/frame assemblies and the relatively high cost of the film can result in greater material costs, causing this form of packaging to be more costly than other forms of packaging. Where the product being packaged does not warrant the very high levels of protection provided by suspension packaging, the cost of the packaging is frequently not justified.
A less costly alternative to suspension packaging is frequently referred to as retention packaging. One version of retention packaging utilizes a corrugated frame including a rigid border extending around the entire periphery of a window opening, and side legs and end legs foldably connected to and supporting the border. A flexible film is connected to the underside of the border so that it extends across the window opening. An article to be packaged is placed on the film, and a series of four rigid flaps connected to the four sides of the border are folded over the article to hold the article in place against the film. In a variant of this package, disclosed in U.S. Pat. No. 5,893,562 to Devin C. Ridgeway, the rigid border is eliminated, the flexible film is connected to the folding side legs, and only two rigid flaps are foldably connected to the side legs to hold the article in place against the film. This variant provides increased structural rigidity while reducing the overall size of the package.
Since retention packaging utilizes only one film/frame assembly and less film, such packaging may provide cost savings over suspension packaging. However, because retention packaging holds an article in place between a film and one or more rigid panels, it does not provide the same degree of protection as is provided by suspension packaging. Moreover, the need to insert the article to be packaged between the rigid panel and the film makes retention packaging less conducive to assembly line procedures than suspension packaging.
In view of the foregoing, there exists a need for improved packaging structures which provide many of the advantages of both suspension packaging and retention packaging. Such improved packaging structures preferably will exhibit an efficient use of corrugated materials and better control of the amount of plastic film used. As a result of these efficiencies, such packaging structures may provide a cost saving to the end user. Furthermore, the more efficient use of materials may facilitate the disposal of these packaging structures after use.